Two or more transistor device to energize a driving coil

ABSTRACT

A switching circuit for energizing a magnetic oscillating driving system for a time-keeping device, comprising driving coil means for controlling the magnetic oscillating driving system, switching means controlled by impulses of a constant frequency, said switching means including at least one transistor responsive to the impulses of constant frequency, said switching means energizing said driving coil means, a delay network connected to the input of the switching means for delaying the response of said switching means to the impulses of constant frequency whereby the switching means provides output pulses of narrower widths than the width of the impulses of constant frequency, said switching means consisting of an additional transistor connected in parallel across the output of the transistor responsive to the impulses of constant frequency, and control coil means responsive to the magnetic system for controlling the additional transistor in accordance with the movement of the magnetic system.

United States Patent 2] Inventor Hens Flaig Schramberg-Sulgen, Wurttemberg, Germany [21] Appl. No. 711,267 [22] Filed Mar. 7,1968 [45] Patented Aug. 3, 1971 73] Assignee Gerbruder Junghans Gessellschatt Mit Beschrankter lhftung Schramberg, Wurttemberg, Germany [3 2] Priority Mar. 9, 1967 [33] Germany [31 1 .I 33 17s [54] TWO OR MORE TRANSISTOR DEVICE TO Primary Examiner-Donald D. Forrer Assistant Examiner-R. C. Woodbridge Att0rney-Watson, Cole, Grindle and Watson ABSTRACT: A switching circuit for energizing a magnetic oscillating driving system for a time-keeping device, comprising driving coil means for controlling the magnetic oscillating driving system, switching means controlled by impulses of a constant frequency, said switching means including at least one transistor responsive to the impulses of constant frequency, said switching means energizing said driving coil means, a delay network connected to the input of the switching means for delaying the response of said switching means to the impulses of constant frequency whereby the switching means provides output pulses of narrower widths than the width of the impulses of constant frequency, said switching means consisting of an additional transistor connected in parallel across the output of the transistor responsive to the impulses of constant frequency, and control coil means responsive to the magnetic system for controlling the additional transistor in accordance with the movement of the magnetic system.

Lst

PATENTEDAUG 319?! 13,597,634

sum 1 or 4 A Fig.2

' Fig. 3

Fig. 4

IN VEN TOR.

PATENTED AUG 3 |97l 3 597.634

sum 2 OF 4 UCE -- Fig.7

UCE A Fig.8

Fig.9

UCE

INVENTOR.

PAIENTEI] AUG 3:971

SHEET U 0F 4 INVENTOR.

'llWG OR MORE TRANSISTGR DEVICE 'llO ENERGIZE A DRIVING COIL The invention relates to a switching arrangement for driving a timekeeping device from a rotating and oscillating driving system, and more particularly to a watch driving system con trolled through impulses ofa constant frequency and which includes at least one transistor which is fed the constant frequency impulses to energize the driving coil of a magnetic system which is movable relative to the driving coil.

A driving system such as a unidirectional rotating motor or any oscillator, for energizing the index plate ofa watch may be driven by impulses of a certain frequency. These lower frequency impulses are produced independently of the movement of the driving system, for example, by means of higher frequency impulses which are produced in an oscillator circuit stabilized by a quartz crystal. The high frequency impulses are lowered in frequency by frequency division to provide symmetrical changing impulses for the drive system which, control an amplifier for producing only impulses of one polarity and wherein the ratio of pulse duration to pulse interval equals unity. That, however, means that, during half of the period of movement of the movable part of the driving system, a driving current will flow although the driving coil will only be in the magnetic field of the magnetic system a fraction of the time. Therefore, from time to time a driving current will flow which has no effect on the movable part ofthe driving system, resulting in a less efficient and effective system.

In accordance with the invention, there is provided a switching arrangement of the aforementioned type which is a simple structure and operates with a high degree of effectiveness. According to the invention, this is achieved by means of a capacitor which is switched in parallel to the input circuit of a transistor and providing a resistance in the feed line to the parallel circuit of input circuit and capacitor. Consequently, the rise time of the control voltage at the control electrode of the transistor will be delayed and the width of theoutput impulses will be less than the width of the control impulses because of the delay until the control voltage reaches the input voltage threshold of the transistor. The desired width of the impulse can be varied through selection of the time constant ofthe resistance and capacitance.

If, additionally, a diode is included between the capacitor and input electrode, then a further voltage increase will be required at the capacitor, until the transistor can be modulated, so that the width of the input voltage impulses will be decreased. By the foregoing means it will be possible to achieve the current impulses which permeate the driving coil which flow only as long as the coil is in the magnetic field, resulting in a maximum degree of effectiveness.

The output ofa second transistor may be switched in paral' lel to the output ofa transistor controlled by the impulses ofa fixed frequency. The control circuit of the second transistor includes a control coil which is acted upon by the magnetic system moved in relation to the control coil. In this embodiment at part of the drive takes place through automatic control of the moved system, while an additional drive is obtained by means of the control impulses of a fixed frequency, thereby achieving synchronization of thesystem.

When using an oscillating driving system, the time constant of the RC element is preferably selected in such a manner that it is essentially smaller than the natural oscillation period of the oscillating system.

The following description of the invention is explained in more detail with respect to several embodiments and reference to the following figures, wherein:

FIG. I shows a circuit diagram of a circuit arrangement according to the invention,

FIG. 2 shows schematically a driving system fed by the circuit arrangement according to FIG. 1,

FIG. 3 shows a graphic presentation of the open circuit voltage at a large oscillation amplitude and produced in the driving coil through the relatively moved magnetic system,

FIG. 4 is a graphic presentation of the open circuit voltage at a small oscillation amplitude and produced in the driving coil through the relatively moved magnetic system,

FIG. 5 is a graphic presentation of the control impulses of a constant frequency, fed to the input of the switching arrangement according to FIG. ll,

FIG. 6 is a graphic presentation of the voltage impulses occurring on the base of the transistor in the circuit according to FIG. I,

FIG. 7 is a graphic presentation of the impulses flowing through the driving coil in the case of a missing or nonmoved magnetic system,

FIG. 8 represents the driving coil impulse waveform of a magnetic system oscillating with a relatively low amplitude wherein the frequency of the control impulses equals the natural frequency of the mechanical oscillating system,

FIG. 9 represents the driving coil impulse waveform of a magnetic system oscillating with a relatively low amplitude wherein the frequency of the control impulses are less than the natural frequency of the mechanical oscillating system,

FIG. 10 represents the driving coil impulse waveform of a magnetic system oscillating with a relatively low amplitude wherein the frequency of the control impulses are greater than the natural frequency of the mechanical oscillating system,

FIG. 11 shows a modification of the embodiment of FIG. 1, including a switching arrangement which is automatically controlled by means of the moved system,

FIG. 12 shows a modification of the embodiment shown in FIG. 11, including an automatic starting feature, and,

FIG. 13 shows the complete circuit diagram of a quartz clock with the switching arrangement according to the invention.

In FIG. 1, the transistor has been designated by Tr, in the output circuit of which there is a coil L in series with a voltage source E. The coil L is the driving coil for an oscillating or rotating system, for example, a balance oscillator as shown in FIG. 2. In this case, we are dealing with a balance oscillator which carries a permanent magnetic system which forms two magnetic airgaps at the peripheral portions of the oscillator which are permeated by the magnetic flux in the opposite sense. The driving coil L and the magnetic airgaps are selected in such a manner that in the rest position of the oscillator, the active sides of the coil L are located in the air gaps.

Capacitor C is inserted in the base-emitter circuit of the transistor Tv and is connected via a resistance R to the voltage source UE supplying the control impulses. The control impulses may be produced by an oscillating circuit synchronized by a quartz, which is connected to a frequency dividing network in order to lower the frequency of the impulses. In order to be able to achieve an effective drive, the movement frequency of the rotating or oscillating system has been adapted to the frequency ofthe control impulses, that is to say, preferably the impulse frequency and the natural frequency of the moved system are the same.

The RC network in the input'circuit of the transistor Tr, provides a relatively slowly rising voltage at the base of the transistor. Since the transistor will be modulated only at a certain threshold voltage, a pulse width reduction in the output impulses in relation to the pulse width of the impulses supplied by the voltage source UE is obtained.

In order to achieve a further reduction in the width of the output impulses, a diode D can be inserted between the capacitor C and the base of the transistor Tr, which will increase the voltage value from which the transistor Tr is being modulated. As a result, the width of the output impulses will be further decreased.

By means of decreasing the width of the output impulses, a current will essentially only flow in the coil L whenever the coil sides are located in the magnetic airgaps of the magnetic system as shown in FIG. 2. As a result, an unnecessary consumption of current will be avoided. In the case of a system oscillating with only a very small amplitude, this will also insure that a braking force will not be exerted on the oscillator.

Through operation of the oscillating magnetic system, shown in FIG. 2, a countervoltage; will be induced in the driving coil L. This countervoltage, in the case of a large oscillation amplitude, will have the form shown in FIG. 3, in the case of a small oscillation amplitude it will have the form shown in FIG. 4. FIGS. 3 and 4 show the countervoltage in the case where no control impulses occur at the transistor input, therefore, so to speak, in no load operation.

FIG. 5 shows the impulses UE occurring at the input of the circuit. Their waveshape is changed through the RC member according to FIG. 6. FIG. 7 shows the output impulses of the circuit which flow through the driving coil L when the oscillator or the rotating system do not move.

FIGS. 8 to 10 show graphic presentations of the voltage impulses across the driving coil L and for the condition wherein the oscillator is oscillating with a low amplitude and wherein the control impulses are according to FIG. 7. FIG. 8 shows the case where the period of movement of the moved mechanical system is equal to the impulse frequency. In the case of the presentation according to FIG. 9, the impulse frequency has been decreased as compared to the natural frequency of the moved system, and in the case of the presentation according to FIG. 10, the impulse frequency has been increased.

FIG. 11 shows a modification of the switching arrangement wherein a second transistor Tr, has been connected in parallel to the output of the transistor Tr. The control circuit of said second transistor includes a control coil L which can be preferably arranged, in close proximity to the driving coil L, or which can be wound together with it. In order to prevent the occurrence of constant feedback oscillations, an inverse feedback capacitor C, has been provided. Therefore, the moved system, according to FIG. 2, is driven by impulses flowing through the driving coil L, which are partially supplied by the transistor Tr, which is automatically controlled by the moved system. For the other part, the drive takes place through impulses which are supplied by the input control impulses.

FIG. 12 shows a modified switching arrangement of the embodiment shown in FIG. 11 wherein a capacitor C has been provided in the input circuit of the transistor Tr,, and is connected via a resistance R, with the source of voltage E. In this manner a bias voltage will be produced at the base of the transistor Tr,, which is influenced by the voltage induced in the control coil L In this manner, in the case of a stopped oscillator, the base voltage of the transistor Tr, is so high that the circuit provides feedback oscillations, as a result of which the mechanical system is started up from its rest position. Through the impulses produced in the control coil L in the case of'a moved mechanical system, the capacitor C is then either charged in the opposite direction or its charge decreased so that the feedback oscillation will be suppressed.

FIG. 13 shows an exemplary embodiment of a total circuit diagram of a quartz clock using the switching arrangement according to FIG. 1. In this circuit, high frequency oscillations will be produced by an oscillator circuit I, which is stabilized with the help of a quartz crystal. An inverter reversing and coolation separating stage are included in the oscillating circuit to provide an output to control a frequency divider stage in the form ofa bistable multivibrator II. The required number of frequency divider stages IIn be provided such that the voltage at the last frequency divider stage has a frequency which corresponds to the natural frequency of the oscillator S in drive circuit III which serves as the driving motor for an index plate, not shown. Naturally it is also possible to use a rotating motor instead of an oscillator S, whose speed has been tuned to the voltage taken from the last frequency divider step.

Iclaim:

l. A switching circuit for energizing a magnetic oscillating driving system for a timekeeping device, comprising driving coil means for controlling the magnetic oscillating driving system, switching means controlled by impulses of a constant frequency, said switching means including at least one transistor responsive to the impulses of constant frequency,

said switchin means energizing said driving coil means, a delay networ connected to the input of the switching means for delaying the response of said switching means to the impulses of constant frequency whereby the switching means provides output pulses of narrower widths than the width of the impulses of constant frequency, said switching means consisting of an additional transistor connected in parallel across the output of the transistor responsive to the impulses of constant frequency, and control coil means responsive to the magnetic system for controlling the additional transistor in accordance with the movement of the magnetic system.

2. A switching circuit according to claim 1, wherein the time constant of the resistance and capacitance is less than the natural oscillation period of the magnetic oscillating system. 

1. A switching circuit for energizing a magnetic oscillating driving system for a timekeeping device, comprising driving coil means for controlling the magnetic oscillating driving system, switching means controlled by impulses of a constant frequency, said switching means including at least one transistor responsive to the impulses of constant frequency, said switching means energizing said driving coil means, a delay network connected to the input of the switching means for delaying the response of said switching means to the impulses of constant frequency whereby the switching means provides output pulses of narrower widths than the width of the impulses of constant frequency, said switching means consisting of an additional transistor connected in parallel across the output of the transistor responsive to the impulses of constant frequency, and control coil means responsive to the magnetic system for controlling the additional transistor in accordance with the movement of the magnetic system.
 2. A switching circuit according to claim 1, wherein the time constant of the resistance and capacitance is less than the natural oscillation period of the magnetic oscillating system. 